Macromolecular dictionary (mmCIF) version 2.0.09

_atom_site_anisotrop.B[2][3]

Name:'_atom_site_anisotrop.B[2][3]'

Definition:

The [2][3] element of the anisotropic atomic displacement
matrix B, which appears in the structure-factor term as:
T = exp{-1/4 sum~i~[sum~j~(B^ij^ h~i~ h~j~ a*~i~ a*~j~)]}
h = the Miller indices
a* = the reciprocal space cell lengths
These matrix elements may appear with atomic coordinates
in the ATOM_SITE category, or they may appear in the separate
ATOM_SITE_ANISOTROP category, but they may not appear in both
places. Similarly, anisotropic displacements may appear as
either B's or U's, but not as both.
The unique elements of the real symmetric matrix are
entered by row.
The IUCr Commission on Nomenclature recommends against the use
of B for reporting atomic displacement parameters. U, being
directly proportional to B, is preferred.